Rat intestinal glycolipids. II. Distribution and biosynthesis of glycolipids and ceramide in villus and crypt cells

Abstract

Intestinal epithelial cells were isolated from rat intestine and grouped into villus and crypt cell fractions. Glycolipids were purified from each cell fraction and quantitated by fluorimetric determination of glycolipid sphingosine. Significant quantities of ceramide were found in all cell fractions and accounted for approximately 15% of total glycolipid sphingosine. While villus and crypt cell fractions quantitatively contained differing amounts of sphingosine, all cell fractions contained proportionally similar quantities of sphingosine when compared to cellular cholesterol or phospholipid. Individual glycolipids, however, showed significant differences in distribution between villus and crypt cells. Hematoside and glucosylceramide were proportionally increased in villus cells, while crypt cells showed an increase in trihexosylceramide and ceramide content. The rate of UDPglucose : hydroxy fatty acid ceramide glucosyltransferase was higher in villus cells while the rate of UDPgalactose : lactosylceramide galactosyltransferase was 3--4 times increased in crypt cells. These studies demonstrate that significant differences in both the distribution and biosynthesis of individual glycolipids occur in crypt and villus cells of rat intestine and are of possible importance in the process of intestinal cell differentiation.